Antigenic variability of an immunodominant region (239-261) of the surface glycoprotein of HTLV-I.

In the 239-261 region of the surface glycoprotein of HTLV-I, we delineated five epitopes recognized by antibodies present in sera from HTLV-I infected patients. Three epitopes are located between the amino acids 252 and 261, one is of a linear type and the two others of a conformational type. One epitope is comprised between amino acids 244 and 249. The last epitope described lies between the amino acids 244 and 257 and strictly requires the presence of a serine at position 250 for its recognition. When patients are infected by viral isolates presenting a substitution of the serine at position 250 by a proline, no antibodies recognizing the 244-257 region could be found. Altogether, our data demonstrate that the immunodominant 239-261 region is complex and is subject to antigenic variability.